A giant swarm of bees descended on rush-hour commuters in London on Tuesday evening, spooking pedestrians, landing on street lamps and slowing traffic to a crawl.

“While I was videoing them I looked down and I could see literally the front of me covered in bees. They were on me. They were on everybody. They were in your hair, on your top,” local shop owner Abigail Hering told the Telegraph.

Phil Clarkson, a beekeeper at Brockley Bees, and his wife, Tracey, brought a mobile hive to the area and stayed for several hours to help calm the swarm.

Nobody was stung, Clarkson told the Telegraph, adding the bees might have come from a nearby park.

Swarming in urban environments may seem strange, but it’s not that uncommon in areas with parks and gardens, according to Jessica Chrustic, an independent beekeeper and educator in New York City.

“As far as urban environments, it really amounts to where the bees are. If there’s a source of pollen and nectar in any environment, it doesn’t really matter whether they’re urban or not,” Chrustic told The Post.

Bee swarms are normal in the late spring and early summer, when hives expand due to population growth. Each of those bee hives depends on a queen to release pheromones telling workers and the hive what to do.

“If the population gets so large that her pheromones aren’t reaching all those workers, the workers will recognize they need to take her, move on and let some of the workers in the hive start creating a new queen,” Chrustic said.

A swarm of bees may be alarming, but they aren’t anything to worry about. Bees are not that aggressive to begin with — and swarms are even less so, according to Chrustic.

“They’re really unlikely to bother anyone because they’re in quite a vulnerable state,” Chrustic said, adding that the worker bees gorge themselves with food in preparation for the flight.

“Because they’re not protecting any honey source or any of their eggs, which are called brood, and they’re only protecting the queen, the bees are really only focused on finding a new home,” she added.